A new UCLA Health study published in JAMA Network Open reveals that overall diabetes medication adherence among 587,000 Medicare Advantage patients in 2019 was below 60 percent, with Black and Hispanic patients showing significantly lower adherence rates than White patients across essential drug therapies.
National Diabetes Medication Adherence Falls Below 60 Percent
Medication adherence remains one of the most stubborn public health challenges facing the U.S. healthcare system, particularly among patients managing chronic conditions like diabetes. A large-scale analysis of national health records combed the records of 587,000 Medicare Advantage patients to evaluate how consistently individuals follow prescribed treatment protocols. The findings show that overall adherence across the cohort sat at less than 60 percent.
Retrospective analyses of pharmacy claims databases provide a clear picture of how frequently patients miss doses or stop treatments altogether. Research examining a cohort of over 200,000 patients treated with noninsulin medications found that 69 percent of patients were adherent when evaluated over a 12-month window. Across broader chronic disease populations, public health experts estimate that half of all maintenance medications are not taken as prescribed, leading to higher rates of hospitalization and disease progression.
Racial Disparities in Metformin and Advanced Diabetes Therapies
The UCLA Health study uncovered stark racial disparities in how patients stick to their medication schedules. Black and Hispanic patients were consistently less likely than White patients to adhere to their prescribed regimens. These gaps persisted even when examining low-cost, widely accessible medications.
Researchers observed an unexpected divide when analyzing individual drug classes, which included metformin, insulin, and a combined group of SGLT2 inhibitors and GLP-1 receptor agonist therapies. Patients were categorized as adherent if they maintained coverage for at least 80 percent of their treatment days.
Researchers were surprised to find that Black patients had significantly lower adherence to metformin, compared to White patients (46 percent vs. 56.5 percent) even though metformin in a low-cost, widely available drug.
The existence of these treatment gaps in inexpensive drugs like metformin demonstrates that financial barriers do not tell the entire story. Non-financial obstacles, such as pharmacy closures, complex dosing schedules, side effects, or personal beliefs about treatment, heavily influence whether patients maintain their regimens.
Financial Support Programs and Out-of-Pocket Costs
While non-financial factors matter, out-of-pocket costs and health plan rules remain primary drivers of non-adherence. Financial assistance programs play a vital role in closing these gaps, specifically Medicaid and Medicare’s Part D Low-Income Subsidy. These programs provide crucial relief for patients prescribed high-cost treatments like insulin and newer drug classes.
System-level factors heavily influence patient habits. Analysis of pharmacy claims data indicates that older age, male sex, higher household income and education, mail-order pharmacy use, and lower out-of-pocket expenses are independently associated with higher adherence. Conversely, patients who are new to diabetes therapy face a significantly higher risk of dropping their medication regimens.
The Massive Economic Toll of Medication Non-Adherence
The consequences of skipped doses stretch far beyond individual health outcomes, creating a heavy financial burden for the entire healthcare infrastructure. Chronic non-adherence costs U.S. health care systems between $100–290 billion annually. Patients who fail to take their medications as directed require an average of three additional medical visits per year, which drives up treatment costs by an average of $2,000 annually per patient.
Targeted public health interventions offer a path toward substantial savings. Studies conducted among veteran populations estimate that improving diabetes medication adherence could yield annual cost savings ranging from $661 million to $1.16 billion.
Future Research Directions and High-Risk Communities
Addressing these systemic disparities requires identifying the exact obstacles preventing vulnerable populations from maintaining their health. More than 34 million people in the United States live with a diagnosis of type 2 diabetes, and 1 in 4 adults aged 65 and older are affected. Furthermore, Black and Hispanic adults experience diabetes rates that are 47 percent and 31 percent higher than those of White adults, respectively.
“Future research must pinpoint specific obstacles – such as pharmacy closures, dosing complexity, side effects or personal beliefs about treatment – so targeted programs can better support high-risk communities.”
As health systems evaluate scalable interventions, researchers emphasize that universal solutions will fall short without addressing both the economic and structural barriers that prevent high-risk patients from receiving continuous care.